Roots-type and screw-type positive displacement compressors are employed in industrial and automotive applications. The compressor or supercharger may be operatively connected to an internal combustion engine to increase the volume of intake air communicated to the internal combustion engine thereby increasing the volumetric efficiency thereof. The supercharger typically includes two interleaved and counter-rotating rotors each of which may be formed with a plurality of lobes to convey intake air for subsequent introduction to the internal combustion engine. The efficiency of the supercharger is dependent on the running clearances between each of the two rotors and a housing within which the two rotors are rotatably supported.